Abstract: To study the strength characteristics of soybean meal, a series of direct shear tests of soybean meal were carried out using a direct shear apparatus for grain.The stress-strain rules of soybean meal under different vertical stresses and shear rates were analyzed. Based on the analysis of the applicability of each elasticity coefficient in Duncan-Chang model, five basic parameters of Duncan-Chang model of soybean meal were obtained. The interlock stress was 5.23 kPa, the internal friction angle was 35.35°, the damage ratio was 0.802 1, the initial tangent modulus cardinal number was 46.259, and the index was 0.886 9. The stress-strain results predicted by the model were compared with the experimental results. The results showed that the predictions made by the proposed model were in good agreement with the results of direct shear tests. It is proved that it is reasonable to use Duncan-Chang model in describing the shear deformation characteristics of soybean meal.